In Blue Earth County, Minnesota, building-permit requirements vary by project and the property owner must confirm what is required1. The county handles permits for most townships, while Lime and Mankato Townships use the City of Mankato1. County zoning applies in unincorporated areas, and the county handles septic permits23.
At a glance
- Building permit
- Requirements vary; issued by the county except in Lime and Mankato Townships, which use the City of Mankato1
- Zoning
- Yes, countywide, administered by the county's Planning & Zoning division2
- Septic (SSTS) permit
- Issued by Blue Earth County Property and Environmental Resources Department3
- Owner-builder exemption
- Available statewide from residential contractor licensing if you occupy or rent the home yourself45
- Floodplain permit
- Required for building, fill or a culvert/bridge within the mapped floodplain6
- Manufactured home
- Must be inspected under federal installation standards before occupancy7
Who to call
Building permits
Blue Earth County Property and Environmental Resources Department (Building Permits)
Building permits for unincorporated Blue Earth County townships, except Lime and Mankato Townships
Zoning
Blue Earth County Planning & Zoning
Zoning district questions, permitted and conditional uses, setbacks and lot-area regulations for unincorporated Blue Earth County
410 S. 5th St., Mankato, MN 56001
Septic permits
Blue Earth County Property and Environmental Resources Department (Wells and Septic)
SSTS (septic) design review, soil verification, permitting and inspection for unincorporated Blue Earth County
410 S 5th St., PO Box 3566, Mankato, MN 56001
Floodplain permits
Blue Earth County Property and Environmental Resources Department (Floodplain Management)
Floodplain determinations and floodplain-ordinance compliance for unincorporated Blue Earth County
410 S. 5th St., Mankato, MN 56001
Contact details are copied from each office’s official page and were checked against it on September 29, 2026.
Do you need a building permit in Blue Earth County, Minnesota?
It depends on the project. Blue Earth County says permit requirements may vary and makes the property owner responsible for confirming whether a permit is required1. The Minnesota State Building Code applies statewide to covered construction, reconstruction, alteration and repair, but agricultural buildings have limited statutory exceptions8. Every Blue Earth County township except Lime Township and Mankato Township routes building permits through the county's Property and Environmental Resources Department; land in those two townships uses the City of Mankato instead1. Call the correct office with your parcel and project details before starting work.
Who issues building permits in Blue Earth County, and how do you reach them?
For most Blue Earth County townships, call the Property and Environmental Resources Department at (507) 304-42519. If your land is in Lime Township or Mankato Township, contact the City of Mankato at (507) 387-8600 instead19. The office with jurisdiction should determine whether the particular project needs a permit because Blue Earth County does not describe every project as automatically permitted or exempt1. When a Minnesota State Building Code permit is required, the work must remain accessible and exposed for inspection, and the permit holder must keep the inspection record card until final approval10.
Does Blue Earth County have zoning?
Yes. Blue Earth County administers a zoning ordinance (Code of Ordinances Chapter 24), and all uses in unincorporated areas must comply with the county's zoning and land-use provisions2. The county's Planning & Zoning division describes zoning as dividing land into districts that set permitted and conditional uses, yard and lot-area rules, and setbacks, with that authority delegated by the state to counties, cities and townships alike11. Minnesota limits this particular county planning-and-zoning statute to counties under 300,000 population by the 1950 census, which Blue Earth County qualifies under12. Call Blue Earth County Planning & Zoning at (507) 304-4251 to confirm your parcel's district and its specific rules before you buy11.
How do septic (SSTS) permits work in Blue Earth County?
Blue Earth County's Property and Environmental Resources Department issues septic (SSTS) permits, verifies soils with septic designers and reviews designs313. A new septic installation receives a site inspection while it is being installed, and the county issues a certificate of compliance only after the system passes14. The county's environmental protection standards apply countywide, including Lime and Mankato Townships13. Only 2.7% of Blue Earth County soils are rated free of severe limits for a conventional drain field, so obtain soil verification before assuming a standard system will work15. Most systems receive local construction permits; systems designed for more than 10,000 gallons per day require an MPCA permit16.
Can you live in an RV or tiny home on your land in Blue Earth County?
Blue Earth County zones the entire unincorporated county, so whether an RV or tiny home can be lived in on a given parcel depends on that parcel's zoning district rather than being open by default211. A manufactured home is a separate case: Minnesota requires every new manufactured home installed for occupancy to be inspected under federal installation standards (CFR 3285 and 3286) before it can be occupied7. We could not confirm Blue Earth County's specific rules on RV occupancy on a residential lot, or on living in an RV while you build a permanent home, from an official county page; call Planning & Zoning at (507) 304-4251 before you buy with that plan11.
Building a home in Blue Earth County, Minnesota: the steps, in order
- Confirm jurisdiction: call Blue Earth County Planning & Zoning at (507) 304-4251 for most townships, or the City of Mankato at (507) 387-8600 for Lime Township or Mankato Township119.
- Confirm the parcel's zoning district and, for a proposed land split, whether each residential lot meets buildable-area, septic-site and access standards217.
- Ask the County Engineer whether a driveway or field entrance in a county right-of-way needs written access approval before work begins18.
- If the site will use septic, arrange soil verification and design review with the county before construction13.
- Confirm whether the project requires a building permit and apply through the office with jurisdiction1.
- Keep permitted work exposed for required building inspections, and arrange the county's installation inspection before using a new septic system1014.
What to check before you buy land in Blue Earth County, Minnesota
Confirm the permit office and project requirements first: most Blue Earth County townships use the county, while Lime Township and Mankato Township use the City of Mankato1. Confirm zoning, setbacks and lot-area rules with Planning & Zoning211. For a proposed land division, verify that each residential lot has sufficient buildable area, a septic site and lawful access; a property split does not necessarily create a right to a new county-road entrance1718. A driveway or field entrance within a county right-of-way needs written authorization before construction, alteration or a change of use18. Check floodplain constraints with the county19. Finally, obtain septic soil verification: only 2.7% of county soils are rated free of severe limits for a conventional drain field1513.
Watch-outs
- Lime Township and Mankato Township are the exception to Blue Earth County's own building-permit process: land there gets its permit from the City of Mankato, not the county9.
- A Blue Earth County property split does not guarantee a new county-road access, and a driveway or field entrance in the county right-of-way requires approval from the County Engineer18.
- Only 2.7% of Blue Earth County's soils are rated free of severe limits for a conventional septic drain field, so budget for a full site evaluation and possibly an alternative system15.
- New construction in the flood fringe must sit on fill high enough that the lowest floor, including the basement, is above the 100-year flood level19.
Sources
- Building Permit Information, quoted and re-checked
- Blue Earth County Code of Ordinances – Ch. 24 Zoning (2026 county census)
- Blue Earth County – Septic Systems (2026 county census)
- Sec. 326B.805 MN Statutes (2026 county census)
- Sec. 326B.805 MN Statutes (Minnesota statewide rule), quoted and re-checked
- Floodplain Regulations (Minnesota statewide rule), quoted and re-checked
- Manufactured home information (Minnesota statewide rule), quoted and re-checked
- 2025 Minnesota Statutes, section 326B.121 (Minnesota statewide rule), quoted and re-checked
- Blue Earth County Property and Environmental Resources Department (Building Permits) (blueearthcountymn.gov)
- 1300.0210 INSPECTIONS (Minnesota statewide rule), quoted and re-checked
- Blue Earth County Planning & Zoning (blueearthcountymn.gov)
- Minnesota Statutes 2025, section 394.21: Authority to Carry on County Planning and Zoning (Minnesota statewide rule), quoted and re-checked
- Blue Earth County Property and Environmental Resources Department (Wells and Septic) (blueearthcountymn.gov)
- Septic Systems, quoted and re-checked
- Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
- SSTS design (Minnesota statewide rule), quoted and re-checked
- County Code of Ordinances, quoted and re-checked
- Permits, quoted and re-checked
- Blue Earth County Property and Environmental Resources Department (Floodplain Management) (blueearthcountymn.gov)
Written September 29, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.